The questionable relationship of Montinia (Montiniaceae): evidence from a floral ontogenetic and anatomical study

Stevens

2022

American J of Botany

The inflorescences of Solanaceae are unique and complex, which has led to long-standing disputes over floral symmetry mainly due to different interpretations of the cyme-like inflorescence structure. The main disagreements have been over how the phyllomes associated with the flower were arranged relative to the inflorescence axis especially during early flower initiation. Methods: Here we investigated the evolution of inflorescences in Solanaceae by analyzing inflorescence structure in the context of phylogeny using ancestral state reconstruction (ASR) to determine the evolutionary transitions between loosely arranged and tightly clustered inflorescences and between monochasial-like and dichasial-like cymes. We also reconstructed two-and three-dimensional models for 12 solanaceous species that represent both inflorescence and phylogenetic diversity in the family. Results: Our results indicate that the most recent common ancestor of Solanaceae had a loosely arranged and monochasial-like cyme, while tightly clustered inflorescences and dichasial-like cymes were derived. Compared to the known process of scorpioid cyme evolution, Solanaceae achieved their scorpioid cyme-like inflorescences through a previously undescribed way. Along the pedicel, the two flower-preceding prophylls are not in the typical transverse position of dicotyledonous plants; they frequently have axillary buds, and the main inflorescence axis continues in a sympodial fashion. As a result, the plane of symmetry of the flower is 36°from the median, and the inflorescence axis and the two flower-preceding prophylls are symmetrically located along that plane. Conclusions: A better understanding of the morphological evolution of solanaceous inflorescence structure helped clarify the floral symmetry of Solanaceae.

Section: Resultsmentioning

confidence: 99%

Evolution and development of inflorescences and floral symmetry in Solanaceae

Stevens

2022

American J of Botany

“…In Paracryphiales, flowers appear choripetalous, but development has not been studied (Endress 2010a). For the evolution of sympetaly and fluctuations between sympetaly and choripetaly in basal asterids, see also Endress (1997a) and Ronse Decraene et al (2000).…”

Section: New Family Positions With Drastic Changesmentioning

confidence: 99%

Progress and problems in the assessment of flower morphology in higher-level systematics

Endress

Matthews

2012

Plant Syst Evol

Floral features used for characterization of higher-level angiosperm taxa (families, orders, and above) are assessed following a comparison of earlier (precladistic/premolecular) and current classifications. Cronquist (An integrated system of classification of flowering plants. Columbia University Press, New York, 1981) and APG (Angiosperm Phylogeny Group) (Bot J Linn Soc 161:105-121, 2009) were mainly used as the basis for this comparison. Although current circumscriptions of taxonomic groups (clades) are largely based on molecular markers, it is also important to morphologically characterize these new groups, as, in many cases, they are completely novel assemblages, especially at the level of orders and above. Features used in precladistic/premolecular classifications are often much more evolutionarily plastic than earlier assumed. A number of earlier neglected but potentially useful features at higher levels are discussed based on our own and other recent studies. As certain features tend to evolve repeatedly in a clade, it appears that apomorphic features in the strict sense are less helpful to characterize larger clades than earlier assumed, and rather apomorphic tendencies of features are more useful at this level.

“…Some comparative studies of floral ontogeny examining interfamilial relationships have found contrasting evidence, or no evidence, for hypotheses derived from molecular analyses (e.g. Caris et al, 2000Caris et al, , 2002Ronse de Craene et al, 2000;Caris and Smets, 2004;Erbar et al, 2005). However, sequence-based results have found support from developmental surveys (e.g.…”

Section: The Floral Development Perspectivementioning

confidence: 99%

Floral Morphology and Development in Quillajaceae and Surianaceae (Fabales), the Species-poor Relatives of Leguminosae and Polygalaceae

Bello¹,

Hawkins²,

Rudall³

2008

Annals of Botany

Differences in the reproductive development and organization of Quillajaceae and Surianaceae cast doubt on their potential sister relationship. Instead, Quillaja resembles Leguminosae in some floral traits, a hypothesis not suggested by molecular-based phylogenies. Despite implicit associations of zygomorphy with species-rich clades and actinomorphy with species-poor families in Fabales, this correlation sometimes fails due to high variation in floral symmetry. Studies considering specific derived clades and reproductive biology could address more precise hypotheses of key innovation and differential diversification in the order.